Binder resin composition for toner

ABSTRACT

A resin binder composition for toners, containing a polyester resin A which is a polycondensate A of raw materials A containing an alkylene oxide adduct of bisphenol A, an aromatic dicarboxylic acid compound, a trivalent or higher polyvalent raw material monomer which is at least any one members of a trihydric or higher polyhydric alcohol and a tricarboxylic or higher polycarboxylic acid compound, and an amorphous acid modified product A of an α-olefin polymer having 4 or more carbon atoms and 18 or less carbon atoms, the polyester resin A having a softening point of 120° C. or more and 150° C. or less; and a toner for electrostatic image development, containing these resin binder composition for toners. The resin binder composition for toners of the present invention is suitably used for a toner for electrostatic image development which is usable in development of latent images formed in, for example, electrostatic image development method, electrostatic recording method, electrostatic printing method or the like.

FIELD OF THE INVENTION

The present invention relates to a resin binder composition for tonerswhich is usable in development of latent images formed in, for example,electrophotography, electrostatic recording method, electrostaticprinting method or the like, and a toner for electrostatic imagedevelopment containing the resin binder composition.

BACKGROUND OF THE INVENTION

Patent Publication 1 discloses a color toner comprising a toner binder(A), a wax (B), and a colorant (C), characterized in that (A) comprisesa resin (D) containing 1 to 50% by weight of a hydrocarbon group having8 or more carbon atoms, and that (A) has a haze value of 70 or less.

Patent Publication 2 discloses a polyester-based resin composition fortoners, characterized in that the polyester-based resin compositioncontains a compatibilization agent capable of compatibilizing apolyester and a wax in a toner containing a resin binder comprising atleast a polyester and a wax, characterized in that the compatibilizationagent is a product of the polyester reacted with a maleicanhydride-modified polyolefin.

Patent Publication 3 discloses a resin binder composition for toners,containing an amorphous polyester-based resin, comprising a constitutingmoiety derived from a polyester resin and a constituting moiety derivedfrom a modified polypropylene-based polymer A having a carboxylate groupor a carboxylate anhydride group, wherein the constituting moietyderived from a polyester resin and a constituting moiety derived from amodified polypropylene-based polymer A are linked by a covalent bonding,wherein the polymer A is a polypropylene-based polymer which is modifiedat an end with a carboxylic acid compound or an anhydride thereof, eachhaving an unsaturated bond, wherein the amount of the constituting unitderived from the polymer A in the above polyester-based resin is 8 partsby mass or more and 30 parts by mass or less, based on 100 parts by massof a total amount of the alcohol component and the carboxylic acidcomponent forming the constituting moiety derived from a polyesterresin.

Patent Publication 1: Japanese Patent Laid-Open No. 2000-250264

Patent Publication 2: Japanese Patent Laid-Open No. 2005-316378

Patent Publication 3: Japanese Patent Laid-Open No. 2019-008185

SUMMARY OF THE INVENTION

The present invention relates to:

[1] a resin binder composition for toners, containing a polyester resinA which is a polycondensate A of raw materials A containing an alkyleneoxide adduct of bisphenol A, an aromatic dicarboxylic acid compound, atrivalent or higher polyvalent raw material monomer which is at leastany one members of a trihydric or higher polyhydric alcohol and atricarboxylic or higher polycarboxylic acid compound, and an amorphousacid modified product A of an α-olefin polymer having 4 or more carbonatoms and 18 or less carbon atoms, the polyester resin A having asoftening point of 120° C. or more and 150° C. or less; and[2] a toner for electrostatic image development containing a resinbinder composition for toilers as defined in the above [1].

DETAILED DESCRIPTION OF THE INVENTION

In the field of toners for electrophotography, there are needs such ashigh-speed printing and high-image quality, with the developments ofelectrophotographic systems. Among them, it is considered that polyesterresins, particularly crosslinked polyester resins, have excellentlow-temperature fusing ability, hygroscopic resistance, and initial risein charging. However, since high-molecular weight components arecontained in large amounts, it is considered that there are somedisadvantages in low pulverizability and productivity of the toner.

In view of the above, as a means of improving pulverizability of thecrosslinked polyester resin, thereby improving the productivity of thetoner, there is a means of a combined use with a low-softening pointresin containing a large amount of a low-molecular weight componenthaving excellent pulverizability, but the low-molecular weight componentin the low-softening point resin has high hygroscopicity, so that theinitial rise of charging is worsened.

In addition, as a means other than the combined use with thelow-softening point resin, a means of incorporating a crystallineheterogeneous monomer into an amorphous polyester resin, to allow aninterface of the sites themselves having different crystal structures toserve as a starting point of pulverization is considered. For example,in a case where a crystalline macro-monomer having an alkyl group suchas an acid modified product of the α-olefin polymer having 2 or 3 carbonatoms is incorporated into an amorphous polyester resin, the improvementin pulverizability was not confirmed which is assumed to be causedbecause the dispersibility of the crystalline macro-monomer in thepolyester resin is worsened (see, Patent Publications 2 and 3). Inaddition, in a case where an amorphous monomer having an alkyl groupsuch as dodecenylsuccinic anhydride is incorporated into the polyesterresin, although the amorphous monomer would be incorporated into theamorphous polyester in a sufficiently dispersed state, it would not beassumed to form an interface of the sites themselves having differentcrystal structures in the combinations of amorphous monomers themselves,so that the improvement in pulverizability was not confirmed (see, forexample, Patent Publication 1).

The present invention relates to a resin binder composition for tonershaving excellent low-temperature fusing ability, initial rise incharging, hygroscopic resistance, and productivity, and a toner forelectrostatic image development containing the resin binder composition.

The toner for electrostatic image development containing a resin bindercomposition of the present invention exhibits excellent effects inlow-temperature fusing ability, initial rise in charging, hygroscopicresistance, and productivity.

One of the features of the resin binder composition for toners of thepresent invention is in the point that the resin binder compositioncontains a polyester resin A, using an amorphous acid modified product Aof an α-olefin polymer having 4 or more carbon atoms and 18 or lesscarbon atoms. By using the acid modified product A, a polyolefin moietyin the acid modified product A is crystallized in a polyester resin intowhich the acid modified product A is introduced. Therefore, thepulverizability of the polyester resin can be improved which is assumedto be caused because the polyolefin moiety can be homogeneouslydispersed in a state of micro-phase separation.

In addition, the acid modified product A is amorphous. By using theamorphous acid modified product A, the hygroscopic resistance of thepolyester resin is even more improved, as compared to a crystalline acidmodified product A of an α-olefin polymer such as a modifiedpolypropylene-based polymer having a carboxylate group or a carboxylateanhydride group. This is considered to be due to the fact that theamorphous acid modified product A of the α-olefin polymer does not havea melting point, so that the acid modified product is allowed to spreadin a wet state on the toner surfaces even when a hydrophobic polyolefinmoiety is at a low temperature.

The crystallinity of the acid modified product is expressed by acrystallinity index ([softening point/highest temperature of endothermicpeak]) in the same manner as the crystallinity of the resins describedlater. The amorphous acid modified product has a crystallinity index ofexceeding 1.4, preferably exceeding 1.5, and more preferably 1.6 ormore, and less than 0.6, and preferably 0.5 or less. In addition, thosein which a highest temperature of endothermic peak is not detectable arejudged to be amorphous.

The polyester resin A is a polycondensate A of raw materials Acontaining an alkylene oxide adduct of bisphenol A, an aromaticdicarboxylic acid compound, a trivalent or higher polyvalent rawmaterial monomer which is at least any one members of a trihydric orhigher polyhydric alcohol and a tricarboxylic or higher polycarboxylicacid compound, and an amorphous acid modified product A of the α-olefinpolymer having 4 or more carbon atoms and 18 or less carbon atoms. Inthe polyester resin A, it is preferable that the polycondensate A is apolycondensate of

a polycondensate B of raw materials B containing an alkylene oxideadduct of bisphenol A, an aromatic dicarboxylic acid compound, and anamorphous acid modified product A of an α-olefin polymer having 4 ormore carbon atoms and 18 or less carbon atoms, witha trivalent or higher polyvalent raw material monomer.Further, it is preferable that the polycondensate B is a polycondensateof a polycondensate C of raw materials C containing an alkylene oxideadduct of bisphenol A and an aromatic dicarboxylic acid compound, withan amorphous acid modified product A of an α-olefin polymer having 4 ormore carbon atoms and 18 or less carbon atoms.

The polyester resin A in the present invention is a crosslinkedpolyester resin using a trivalent or higher polyvalent raw materialmonomer which is at least any one of a trihydric or higher polyhydricalcohol and a tricarboxylic or higher polycarboxylic acid compound. Inthe present invention, as mentioned above, even a crosslinked polyesterresin which is considered to be usually inadequate in pulverizabilityhas improved pulverizability by using an acid modified product A.

The trihydric or higher polyhydric alcohol includes glycerol,pentaerythritol, and trimethylolpropane, and the like, among whichglycerol is preferred.

The tricarboxylic or higher polycarboxylic acid compound includes1,2,4-benzenetricarboxylic acid (trimellitic acid),2,5,7-naphthalenetricarboxylic acid, pyromellitic acid, or acidanhydrides and alkyl esters of these acids, the alkyl group having from1 to 3 carbon atoms, and the like, among which the trimellitic acidcompounds are preferred.

The content of the trivalent or higher polyvalent raw material monomerin the polyester resin A in the raw materials A other than the acidmodified product A is preferably 2% by mol or more, and more preferably3% by mol or more, from the viewpoint of low-temperature fusing abilityand productivity, and the content is preferably 18% by mol or less, morepreferably 15% by mol or less, and even more preferably 12% by mol orless, from the viewpoint of hygroscopic resistance and initial rise ofcharging.

The raw materials A contain, as an alcohol component, an alkylene oxideadduct of bisphenol A, from the viewpoint of the low-temperature fusingability and the reactivities with the acid modified product A. It ispreferable that the alkylene oxide adduct of bisphenol A is a compoundrepresented by the formula (I):

wherein OR and RO are an oxyalkylene group, wherein R is an ethylenegroup and/or a propylene group; and each of x and y is a positive numbershowing an average number of moles of alkylene oxide added, wherein avalue of the sum of x and y is 1 or more, and preferably 1.5 or more,and 16 or less, preferably 8 or less, more preferably 6 or less, andeven more preferably 4 or less.

The alkylene oxide adduct of bisphenol A represented by the formula (I)includes polyoxypropylene adducts of 2,2-bis(4-hydroxyphenyl)propane,polyoxyethylene adducts of 2,2-bis(4-hydroxyphenyl)propane, and thelike. These alkylene oxide adducts can be preferably used alone or intwo or more kinds.

The content of the alkylene oxide adduct of bisphenol A represented bythe formula (I) in the alcohol component is preferably 70% by mol ormore, more preferably 80% by mol or more, even more preferably 90% bymol or more, and even more preferably 95% by mol or more.

The alcohol component other than the alkylene oxide adduct of bisphenolA and the trihydric or higher polyhydric alcohol includes aliphaticdiols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol,1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-butenediol,1,3-butanediol, and neopentyl glycol, and the like.

The raw materials A contain a carboxylic acid component including anacid modified product A of an α-olefin polymer, and, from the viewpointof storage property, an aromatic dicarboxylic acid compound.

In the acid modified product A of the α-olefin polymer having 4 or morecarbon atoms and 18 or less carbon atoms, the number of carbon atoms ofthe α-olefin polymer is 4 or more, and 18 or less, preferably 10 orless, more preferably 7 or less, even more preferably 5 or less, andeven more preferably 4.

The α-olefin polymer having 4 or more carbon atoms and 18 or less carbonatoms includes polyisobutene-based polymers, poly 1-butene-basedpolymers, poly 1-pentene-based polymers, poly 1-hexene-based polymers,poly 1-octene-based polymers, poly 4-methylpentenc-based polymers, poly1-dodecene-based polymers, poly 1-hexadecene-based polymers,propylene-hexene copolymers, and the like, and among them, thepolyisobutene-based polymers are preferred. The above α-olefin polymermay be a homopolymer of the above α-olefin, or may be a copolymer of twoor more members selected from the above α-olefins, or may be a copolymerof the above α-olefin with another olefin. In addition, the copolymermay be any one of random copolymers and block copolymers.

The polyisobutene-based polymer includes polyisobutenes, copolymers ofisobutene and other olefins, and the like. Other olefins include, forexample, ethylene, butene, pentene, hexene, and 2-ethylhexene. When thepolyisobutene-based polymer is a copolymer, the proportion of isobuteneis preferably 60% by mass or more, more preferably 80% by mass or more,and even more preferably 90% by mass or more, and less than 100% bymass.

On the other hand, the acid modified product A is preferably an acidmodified product in which the α-olefin polymer having 4 or more carbonatoms and 18 or less carbon atoms is modified with at least one acidselected from the group consisting of maleic acid, fumaric acid,itaconic acid, and acid anhydrides thereof, and more preferably an acidmodified product modified with maleic anhydride, from the viewpoint ofthe reactivities with the polyester resin. In addition, the acidmodified product includes an acid modified product in a random graftform in which the above α-olefin polymer is randomly grafted andmodified with an acid, an acid modified product in an end modificationform in which an end of the above α-olefin polymer is modified with anacid, and the like. In the present invention, the acid modified productof an end modification form is preferred, and an acid modified productof a one-end modification form in which one end of the α-olefin polymerhaving 4 or more carbon atoms and 18 or less carbon atoms is modifiedwith an acid is more preferred, from the viewpoint of low-temperaturefusing ability and storage property.

The acid modified product in a random graft form is preferably such thatone molecule of the polymer is grafted with one or more acids andmodified. Whether or not the polymer is modified with an acid can bedefined by a general spectroscopic measurement. For example, in a caseof an acid modified product in a random graft form with maleicanhydride, when the polymer is modified with maleic anhydride, a doublebond of maleic anhydride is changed to a single bond, so that themodification can be defined by the measurement of a spectroscopic changethereof.

The acid modified product in a random graft modification form isobtained by, for example, generating a radical within a molecule of anα-olefin polymer, and reacting the radical with a carboxylic acidcompound or an anhydride thereof having an unsaturated bond.

The acid modified product in an end modification form is preferably onein which one molecule of the polymer is modified with one acid (one-end)or two acids (both-ends). Whether or not the polymer is modified with anacid can be defined by a general spectroscopic measurement. For example,in a case of an acid modified product in a one-end modification formwith maleic anhydride, when the polymer is modified with maleicanhydride, a double bond of maleic anhydride is changed to a singlebond, so that the modification can be defined by the measurement of aspectroscopic change thereof. In addition, since a spectroscopic changetakes place just before and after bonding at the connected portion at aside of the α-olefin polymer, this modification can be defined by themeasurement of the change.

The acid modified product in a one-end form is obtained, for example, bysubjecting the above α-olefin polymer having an unsaturated bond at oneend to an Ene reaction with an acid. The above α-olefin polymer havingan unsaturated bond at one end is obtained by a known method, and thepolymer can be produced by using, for example a vanadium-based catalyst,a titanium-based catalyst, a zirconium-based catalyst or the like.

As described above, it is preferable that the acid modified product A ofthe α-olefin polymer is a polyisobutene succinic anhydride modified withmaleic anhydride at one end.

The weight-average molecular weight of the acid modified product A ispreferably 500 or more, more preferably 700 or more, even morepreferably 900 or more, and even more preferably 1,100 or more, from theviewpoint of storage property, and the weight-average molecular weightis preferably 5,000 or less, more preferably 4,000 or less, and evenmore preferably 3,000, from the viewpoint of low-temperature fusingability.

The content of the acid modified product A, based on 100 parts by massof a total amount of the alcohol component and the carboxylic acidcomponent other than the acid modified product A, i.e., the rawmaterials A other than the acid modified product A, is preferably 3parts by mass or more, more preferably 4 parts by mass or more, evenmore preferably 7 parts by mass or more, even more preferably 9 parts bymass or more, even more preferably 10 parts by mass or more, and evenmore preferably 15 parts by mass or more, from the viewpoint of theinitial rise in charging, hygroscopic resistance, and pulverizability,and the content is preferably 40 parts by mass or less, more preferably30 parts by mass or less, even more preferably 25 parts by mass or less,even more preferably 23 parts by mass or less, and even more preferably20 parts by mass or less, from the viewpoint of low-temperature fusingability and productivity.

The aromatic dicarboxylic acid compound includes phthalic acid,isophthalic acid, terephthalic acid, anhydrides and alkyl esters ofthese acids, the alkyl group having from 1 to 3 carbon atoms, and thelike. Among them, terephthalic acid or isophthalic acid is preferred,and terephthalic acid is more preferred, from the viewpoint oflow-temperature fusing ability.

The content of the aromatic dicarboxylic acid compound in the carboxylicacid component other than the acid modified product A is preferably 80%by mol or more, and more preferably 90% by mol or more, from theviewpoint of storage property.

The carboxylic acid component other than the aromatic dicarboxylic acidcompound and the acid modified product A includes aliphatic dicarboxylicacid compounds, and the like.

The aliphatic dicarboxylic acid compound includes aliphatic dicarboxylicacids such as oxalic acid, malonic acid, maleic acid, fumaric acid,citraconic acid, itaconic acid, glutaconic acid, succinic acid, andadipic acid, and anhydrides and alkyl esters of these acids, the alkylgroup having from 1 to 3 carbon atoms, and the like.

The alcohol component may properly contain a monohydric alcohol, and thecarboxylic acid component may properly contain a monocarboxylic acidcompound.

The polyester resin A can be produced, for example, by polycondensingthe alcohol component and the carboxylic acid component in an inert gasatmosphere at a temperature of preferably 130° C. or higher, and morepreferably 170° C. or higher, and preferably 250° C. or lower, and morepreferably 240° C. or lower, preferably in the presence of anesterification catalyst, further optionally in the presence of anesterification promoter, a polymerization inhibitor or the like.

The esterification catalyst includes tin compounds such as dibutyltinoxide and tin(II) 2-ethylhexanoate; titanium compounds such as titaniumdiisopropylate bistriethanolaminate; and the like. The amount of theesterification catalyst used is preferably 0.01 parts by mass or more,and more preferably 0.1 parts by mass or more, and preferably 1.5 partsby mass or less, and more preferably 1 part by mass or less, based on100 parts by mass of a total amount of the alcohol component and thecarboxylic acid component other than the acid modified product A. Theesterification promoter includes gallic acid, and the like. The amountof the esterification promoter used is preferably 0.001 parts by mass ormore, and more preferably 0.01 parts by mass or more, and preferably 0.5parts by mass or less, and more preferably 0.1 parts by mass or less,based on 100 parts by mass of a total amount of the alcohol componentand the carboxylic acid component other than the acid modified productA. The polymerization inhibitor includes t-butyl catechol, and the like.The amount of the polymerization inhibitor used is preferably 0.001parts by mass or more, and more preferably 0.01 parts by mass or more,and preferably 0.5 parts by mass or less, and more preferably 0.1 partsby mass or less, based on 100 parts by mass of a total amount of thealcohol component and the carboxylic acid component other than the acidmodified product A.

Here, in the present invention, the polyester resin A may be a polyesterresin modified with a material other than an acid to an extent that theproperties thereof are not substantially impaired. The polyester resinmodified with a material other than an acid includes, for example, apolyester resin grafted or blocked with a phenol, a urethane, an epoxyor the like according to a method described in Japanese Patent Laid-OpenNo. Hei-11-133668, Hei-10-239903, Hei-8-20636, or the like. Among themodified polyester resins, urethane-modified polyester resins in whichpolyester resins are urethane-extended with a polyisocyanate compoundare preferred.

It is preferable that the polyester resin A is an amorphous resin. Thecrystallinity of the resin is expressed by a crystallinity index, whichis defined by a ratio of a softening point to a highest temperature ofendothermic peak as determined by a differential scanning calorimeter,i.e. a value of [softening point/highest temperature of endothermicpeak]. The crystalline resin is a resin having a crystallinity index of0.6 or more, preferably 0.7 or more, and more preferably 0.9 or more,and 1.4 or less, preferably 1.2 or less, and more preferably 1.1 orless, and on the other hand, the amorphous resin is a resin having acrystallinity index exceeding 1.4, and preferably exceeding 1.5, andmore preferably 1.6 or more, or a resin having a crystallinity index ofless than 0.6, and preferably 0.5 or less. The crystallinity of theresin can be adjusted in accordance with the kinds and the ratios of theraw material monomers, and the production conditions (for example,reaction temperatures, reaction time, cooling rate) or the like. Here, ahighest temperature of endothermic peak refers to a temperature of thepeak at the highest temperature side out of the observed endothermicpeaks. In a crystalline resin, a highest temperature of endothermic peakis defined as a melting point.

The softening point of the polyester resin A is 120° C. or higher,preferably 125° C. or higher, and more preferably 130° C. or higher,from the viewpoint of hygroscopic resistance and initial rise ofcharging, and the softening point is 150° C. or lower, and preferably145° C. or lower, from the viewpoint of low-temperature fusing ability.

The glass transition temperature of the polyester resin A is preferably40° C. or higher, and more preferably 50° C. or higher, from theviewpoint of storage stability, and the glass transition temperature ispreferably 80° C. or lower, more preferably 70° C. or lower, and evenmore preferably 65° C. or lower, from the viewpoint of low-temperaturefusing ability.

The acid value of the polyester resin A is preferably 5 mgKOH/g or more,and more preferably 10 mgKOH/g or more, from the viewpoint oflow-temperature fusing ability and productivity, and the acid value ispreferably 30 mgKOH/g or less, more preferably 25 mgKOH/g or less, andeven more preferably 20 mgKOH/g or less, from the viewpoint ofhygroscopic resistance.

It is preferable that the resin binder composition of the presentinvention contains a polyester resin B having a softening point lowerthan the polyester resin A, from the viewpoint of low-temperature fusingability.

The softening point of the polyester resin B is preferably 80° C. orhigher, more preferably 85° C. or higher, and even more preferably 90°C. or higher, from the viewpoint of storage property, and the softeningpoint is preferably 115° C. or lower, more preferably 112° C. or lower,and even more preferably 108° C. or lower, from the viewpoint oflow-temperature fusing ability.

In addition, a difference in the softening points between the polyesterresin A and the polyester resin B is preferably 15° C. or more, morepreferably 18° C. or more, and even more preferably 20° C. or more, andpreferably 55° C. or less, more preferably 50° C. or less, and even morepreferably 45° C. or less.

It is preferable that the polyester resin B is amorphous, and it ispreferable that the polyester B is a polycondensate of an alcoholcomponent containing an alkylene oxide adduct of bisphenol A and acarboxylic acid component containing an aromatic dicarboxylic acidcompound. Specific examples of the alkylene oxide adduct of bisphenol Aand the aromatic dicarboxylic acid compound are the same as those forthe polyester resin A.

The content of the alkylene oxide adduct of bisphenol A in the alcoholcomponent is preferably 70% by mol or more, more preferably 80% by molor more, even more preferably 90% by mol or more, even more preferably95% by mol or more, and even more preferably 100% by mol.

The content of the aromatic dicarboxylic acid compound in the carboxylicacid component is preferably 70% by mol or more, more preferably 80% bymol or more, even more preferably 90% by mol or more, even morepreferably 95% by mol or more, and even more preferably 100% by mol.

The glass transition temperature of the polyester resin B is preferably40° C. or higher, and more preferably 50° C. or higher, from theviewpoint of storage stability, and the glass transition temperature ispreferably 80° C. or lower, more preferably 70° C. or lower, and evenmore preferably 65° C. or lower, from the viewpoint of low-temperaturefusing ability.

The acid value of the polyester resin B is preferably 0.3 mgKOH/g ormore, more preferably 0.5 mgKOH/g or more, and even more preferably 0.8mgKOH/g or more, from the viewpoint of low-temperature fusing ability,and the acid value is preferably 12 mgKOH/g or less, more preferably 8mgKOH/g or less, and even more preferably 5 mgKOH/g or less, from theviewpoint of storage property.

The mass ratio of the polyester resin A to the polyester resin B(polyester resin A/polyester resin B) is preferably 60/40 or more, morepreferably 65/35 or more, and even more preferably 70/30 or more, andpreferably 98/2 or less, more preferably 95/5 or less, and even morepreferably 92/8 or less.

The content of the polyester resin A, or a total content of thepolyester resin A and the polyester resin B when the polyester resin Bis contained, in the resin binder composition, is preferably 80% by massor more, more preferably 90% by mass or more, even more preferably 95%by mass or more, and even more preferably 100% by mass.

The resin binder composition of the present invention may contain apolyester resin other than the polyester resins A and B, a vinyl-basedresin such as a styrene-acrylic resin, an epoxy resin, a polycarbonate,a polyurethane, a composite resin containing two or more kinds of theseresins, or the like within the range that would not impair the effectsof the present invention.

The content of the resin binder composition of the present invention inthe toner for electrostatic image development is preferably 50% by massor more, more preferably 60% by mass or more, even more preferably 70%by mass or more, and even more preferably 80% by mass, and preferablyless than 100% by mass, more preferably 98% by mass or less, even morepreferably 95% by mass or less, and even more preferably 92% by mass orless.

The toner for electrostatic image development of the present inventionmay contain, besides a resin binder (a resin binder composition of thepresent invention), an additive such as a colorant, a releasing agent, acharge control agent, a magnetic powder, a flowability improver, anelectric conductivity modifier, a reinforcing filler such as a fibrousmaterial, an antioxidant, or a cleanability improver, and preferablycontains a colorant, a releasing agent, and a charge control agent.

As the colorant, dyes, pigments, magnetic powder, and the like which areused as colorants for toners can be used. Examples include carbonblacks, Phthalocyanine Blue, Permanent Brown FG, Brilliant Fast Scarlet,Pigment Red 122, Pigment Green B, Rhodamine-B Base, Solvent Red 49,Solvent Red 146, Solvent Blue 35, quinacridone, carmine 6B, isoindoline,disazo yellow, and the like. In the present invention, the toner may beany one of black toners and color toners.

From the viewpoint of improving optical density and low-temperaturefusing ability of the toner, the content of the colorant, based on 100parts by mass of the resin binder, is preferably 1 part by mass or more,and more preferably 2 parts by mass or more, and the content ispreferably 40 parts by mass or less, and more preferably 10 parts bymass or less.

The releasing agent (wax) includes aliphatic hydrocarbon waxes such aspolypropylene wax, polyethylene wax, polypropylene-polyethylenecopolymer wax, microcrystalline wax, paraffin waxes, Fischer-Tropschwax, and sazole wax or oxides thereof; ester-based waxes such ascarnauba wax, montan wax or deacidified waxes thereof, and fatty acidester waxes; fatty acid amides, fatty acids, higher alcohols, metalsalts of fatty acids, and the like. These releasing agents can be usedalone or in a mixture of two or more kinds.

The melting point of the releasing agent is preferably 80° C. or higher,more preferably 85° C. or higher, and even more preferably 90° C. orhigher, from the viewpoint of transferability of the toner, and themelting point is preferably 130° C. or lower, more preferably 125° C. orlower, and even more preferably 120° C. or lower, from the viewpoint oflow-temperature fusing ability.

From the viewpoint of low-temperature fusing ability and offsetresistance of the toner and from the viewpoint of dispersibility in theresin binder, the content of the releasing agent, based on 100 parts bymass of the resin binder, is preferably 0.5 parts by mass or more, morepreferably 1 part by mass or more, even more preferably 1.5 parts bymass or more, even more preferably 3 parts by mass or more, and evenmore preferably 4 parts by mass or more, and the content is preferably10 parts by mass or less, more preferably 8 parts by mass or less, andeven more preferably 7 parts by mass or less.

The charge control agent may contain, but not particularly limited to,any of positively chargeable charge control agents and negativelychargeable charge control agents.

The positively chargeable charge control agent includes Nigrosine dyes,for example, “Nigrosine Base EX,” “OIL BLACK BS,” “OIL BLACK SO,”“BONTRON N-01,” “BONTRON N-04,” “BONTRON N-07,” “BONTRON N-09,” “BONTRONN-11” (hereinabove manufactured by Orient Chemical Industries Co.,Ltd.), and the like; triphenylmethane-based dyes containing a tertiaryamine as a side chain; quaternary ammonium salt compounds, for example,“BONTRON P-51” (manufactured by Orient Chemical Industries Co., Ltd.),cetyltrimethylammonium bromide, “COPY CHARGE PX VP435” (manufactured byClariant, Ltd.), and the like; polyamine resins, for example, “AFP-B”(manufactured by Orient Chemical Industries Co., Ltd.), and the like;imidazole derivatives, for example, “PLZ-2001,” “PLZ-8001” (hereinabovemanufactured by Shikoku Chemicals Corporation), and the like;styrene-acrylic resins, for example, “FCA-701PT” (manufactured byFUJIKURAKASEI CO., LTD.), and the like.

In addition, the negatively chargeable charge control agent includesmetal-containing azo dyes, for example, “VARIFAST BLACK 3804,” “BONTRONS-31, “BONTRON S-32,” “BONTRON S-34,” “BONTRON S-36” (hereinabovemanufactured by Orient Chemical Industries Co., Ltd.), “AIZEN SPILONBLACK TRH,” “T-77” (manufactured by Hodogaya Chemical Co., Ltd.), andthe like; metal compounds of benzilic acid compounds, for example,“LR-147,” “LR-297” (hereinabove manufactured by Japan Carlit Co., Ltd.),and the like; metal compounds of salicylic acid compounds, for example,“BONTRON E-81,” “BONTRON E-84,” “BONTRON E-88,” “BONTRON E-304”(hereinabove manufactured by Orient Chemical Industries Co., Ltd.),“TN-105” (manufactured by Hodogaya Chemical Co., Ltd.), and the like;copper phthalocyanine dyes; quaternary ammonium salts, for example,“COPY CHARGE NX VP434” (manufactured by Clariant, Ltd.), nitroimidazolederivatives, and the like; organometallic compounds and the like.

From the viewpoint of electric stability of the toner, the content ofthe charge control agent, based on 100 parts by mass of the resinbinder, is preferably 0.01 parts by mass or more, and more preferably0.2 parts by mass or more, and preferably 10 parts by mass or less, morepreferably 5 parts by mass or less, even more preferably 3 parts by massor less, and even more preferably 2 parts by mass or less.

The toner of the present invention may be a toner obtained by any of theconventionally known methods such as a melt-kneading method, an emulsionphase-inversion method, and a polymerization method, and a pulverizedtoner produced by the melt-kneading method is preferred, from theviewpoint of productivity and dispersibility of a colorant. In a case ofa pulverized toner produced by a melt-kneading method, a toner can beproduced by homogeneously mixing raw materials such as a resin binder, acolorant, a releasing agent and a charge control agent with a mixer suchas a Henschel mixer, thereafter melt-kneading the mixture with a closedkneader, a single-screw or twin-screw extruder, an open-roller typekneader or the like, cooling, pulverizing, and classifying the product.

In the toner of the present invention, an external additive ispreferably used, for the purpose of improving transferability. Theexternal additive includes fine inorganic particles of silica, alumina,titania, zirconia, tin oxide, zinc oxide, and the like, and fine organicparticles of resin particles such as fine melamine resin particles andfine polytetrafluoroethylene resin particles. Two or more kinds of theexternal additives may be used in combination. Among them, silica ispreferred, and a hydrophobic silica that is hydrophobically treated ismore preferred, from the viewpoint of transferability of the toner.

The hydrophobic treatment agent for hydrophobically treating the surfaceof silica particles includes hexamethyldisilazane (HMDS),dimethyldichlorosilane (DMDS), a silicone oil, octyltriethoxysilane(OTES), methyltriethoxysilane, and the like.

From the viewpoint of chargeability, flowability, and transferability ofthe toner, the average particle size of the external additive ispreferably 10 nm or more, more preferably 15 nm or more, and preferably250 nm or less, more preferably 200 nm or less, even more preferably 150nm or less, and even more preferably 90 nm or less.

From the viewpoint of chargeability, flowability, and transferability ofthe toner, the content of the external additive, based on 100 parts bymass of the toner before the treatment with the external additive, ispreferably 0.05 parts by mass or more, more preferably 0.1 parts by massor more, and even more preferably 0.3 parts by mass or more, andpreferably 5 parts by mass or less, and more preferably 3 parts by massor less.

The volume-median particle size D₅₀ of the toner of the presentinvention is preferably 3 μm or more, and more preferably 4 μm or more,and preferably 15 μm or less, and more preferably 10 μm or less. Thevolume-median particle size D₅₀ as used herein means a particle size ofwhich cumulative volume frequency calculated on a volume percentage is50% counted from the smaller particle sizes. Also, in a case where thetoner is treated with an external additive, the volume-median particlesize of the toner is regarded as a volume-median particle size of thetoner particles before the treatment with an external additive.

The toner of the present invention can be used as a toner formonocomponent development, or a toner may be mixed with a carrier to beused as a two-component developer.

The present invention will be described more specifically by means ofExamples, without intending to limit the present invention thereto. Thephysical properties of the resins and the like can be measured inaccordance with the following methods.

[Highest Temperature of Endothermic Peak of Acid Modified Product]

Using a differential scanning calorimeter “DSC Q20,” manufactured by TAInstruments Japan, a 0.01 to 0.02 g sample is weighed out in an aluminumpan, heated from room temperature (25° C.) to 200° C. at a heating rateof 10° C./min, and cooled from that temperature to −10° C. at a coolingrate of 5° C./min. Next, the temperature of the sample is raised to 180°C. at a heating rate of 10° C./min to measure endothermic peaks. One inwhich a highest temperature of endothermic peak is not detected isamorphous, and when detected, a softening point is measured in the samemanner as that of the resin, and a crystallinity index (softeningpoint/highest temperature of endothermic peak) is calculated to bejudged.

[Weight-Average Molecular Weight (Mw) of Acid Modified Product ofα-Olefin Polymer]

(1) Preparation of Sample Solution

A sample is dissolved in tetrahydrofuran so as to have a concentrationof 0.5 g/100 mL. Next, this solution is filtered with a fluororesinfilter “FP-200,” manufactured by Sumitomo Electric Industries, Ltd.,having a pore size of 2 μm, to remove insoluble components, to provide asample solution.

(2) Measurement of Molecular Weight Distribution

Using the following measurement apparatus and analyzing column, themeasurement is taken by allowing tetrahydrofuran to flow through acolumn as an eluent at a flow rate of 1 mL per minute, stabilizing thecolumn in a thermostat at 40° C., and injecting a 100 μL of a samplesolution thereto. The molecular weight of the sample is calculated basedon the previously drawn calibration curve. At this time, a calibrationcurve which is drawn from several kinds of monodispersed polystyrenes,manufactured by Tosoh Corporation, A-500 (Mw 5.0×10²), A-1000 (Mw1.01×10³), A-2500 (Mw 2.63×10³), A-5000 (Mw 5.97×10³), F-1 (Mw1.02×10⁴), F-2 (Mw 1.81×10⁴), F-4 (Mw 3.97×10⁴), F-10 (Mw 9.64×10⁴),F-20 (Mw 1.90×10⁵), F-40 (Mw 4.27×10⁵), F-80 (Mw 7.06×10⁵), and F-128(Mw 1.09×10⁶) as standard samples is used. The values within parenthesesshow molecular weights.

Measurement Apparatus: HLC-8220GPC, manufactured by Tosoh CorporationAnalyzing Column: GMHXL+G3000HXL, manufactured by Tosoh Corporation.

[Softening Point of Resin]

Using a flow tester “CFT-500D,” manufactured by Shimadzu Corporation, a1 g sample is extruded through a nozzle having a diameter of 1 mm and alength of 1 mm with applying a load of 1.96 MPa thereto with a plunger,while heating the sample at a heating rate of 6° C./min. The softeningpoint refers to a temperature at which half of the sample flows out,when plotting a downward movement of the plunger of the flow testeragainst temperature.

[Highest Temperature of Endothermic Peak of Resin]

Using a differential scanning calorimeter “Q-100,” manufactured by TAInstruments, Japan, a 0.01 to 0.02 g sample is weighed out in analuminum pan, and cooled from room temperature (25° C.) to 0° C. at acooling rate of 10° C./min, and kept at 0° C. for one minute.Thereafter, the temperature of the sample is raised at a heating rate of10° C./min to take measurements. Of the endothermic peaks observed, atemperature of the peak at the highest temperature is defined as ahighest temperature of endothermic peak.

[Glass Transition Temperature of Resin]

Using a differential scanning calorimeter “Q-100” (manufactured by TAInstruments, Japan), a 0.01 to 0.02 g sample is weighed out in analuminum pan, the sample is heated to 200° C., and the sample is cooledfrom that temperature to 0° C. at a cooling rate of 10° C./min. Next,the sample is heated at a rate of 10° C./min to take measurements ofendothermic peaks. A temperature of an intersection of the extension ofthe baseline of equal to or lower than the highest temperature ofendothermic peak and the tangential line showing the maximum inclinationbetween the kick-off of the peak and the top of the peak in the abovemeasurement is defined as a glass transition temperature.

[Acid Value of Resin]

The acid value is determined by a method according to JIS K0070:1992except that only the determination solvent is changed from a mixedsolvent of ethanol and ether as prescribed in JIS K0070 to a mixedsolvent of acetone and toluene in a volume ratio of acetone:toluene=1:1.

[Melting Point of Releasing Agent]

Using a differential scanning calorimeter “DSC Q-100,” manufactured byTA Instruments Japan, a 0.01 to 0.02 g sample is weighed out in analuminum pan, heated to 200° C. at a heating rate of 10° C./min, andcooled from that temperature to −10° C. at a cooling rate of 5° C./min.Next, the temperature of the sample is raised to 180° C. at a heatingrate of 10° C./min to take measurements. A highest temperature ofendothermic peak observed from a melting-endothermic curve obtainedabove is defined as a melting point of a releasing agent.

[Average Particle Size of External Additive]

The average particle size refers to a number-average particle size,which is defined as a number-average of particle sizes (average oflength and breadth) determined for 500 particles from a photograph takenwith a scanning electron microscope (SEM).

[Volume-Median Particle Size of Toner]

Measuring Apparatus: Coulter Multisizer II, manufactured by BeckmanCoulter, Inc.

Aperture Diameter: 50 μm

Analyzing Software: Coulter Multisizer AccuComp Ver. 1.19, manufacturedby Beckman Coulter, Inc.Electrolytic Solution: Isotone II, manufactured by Beckman Coulter, Inc.Dispersion: EMULGEN 109P, manufactured by Kao Corporation,polyoxyethylene lauryl ether, HLB (Griffin): 13.6, is dissolved in theelectrolytic solution to adjust to a concentration of 5% by mass toprovide a dispersion.Dispersion Conditions: Ten milligrams of a measurement sample is addedto 5 mL of the above dispersion, and the mixture is dispersed for 1minute with an ultrasonic disperser (name of machine: US-1, manufacturedby SND Co., Ltd., output: 80 W). Thereafter, 25 mL of the aboveelectrolytic solution is added to the dispersion, and further dispersedwith the ultrasonic disperser for 1 minute, to prepare a sampledispersion.Measurement Conditions: The above sample dispersion is added to 100 mLof the above electrolytic solution to adjust to a concentration at whichparticle sizes of 30,000 particles can be measured in 20 seconds, andthe 30,000 particles are measured, and a volume-median particle size D₅₀is obtained from the particle size distribution.

Production Example 1 of Resin

A 10-liter four-neck flask equipped with a dehydration tube equippedwith a nitrogen inlet tube, a stirrer, and a thermocouple was chargedwith an alcohol component as listed in Table 1. The contents were heatedto 100° C., terephthalic acid as listed in Table 1 was then addedthereto, and the mixture was heated to 160° C. An esterificationcatalyst and an esterification promoter as listed in Table 1 were addedthereto, and the mixture was heated to 235° C. and reacted at 235° C.for 10 hours, and then reacted for one hour at 235° C. and 8.0 kPa. Thereaction mixture was cooled to 160° C., and an acid modified product aslisted in Table 1 was added thereto. The temperature was then raisedagain to 235° C., and a polycondensation reaction was carried out at235° C. for 5 hours. Thereafter, the reaction mixture was cooled to 200°C., trimellitic anhydride as listed in Table 1 was added thereto, and apolycondensation reaction was carried out at 200° C. for one hour, andfurther at 200° C. and 8.0 kPa until a softening point reached to avalue as listed in Table 1, to provide each of amorphous polyesterresins (resins A1 to A5, and A9).

Production Example 2 of Resin

A 10-liter four-neck flask equipped with a dehydration tube equippedwith a nitrogen inlet tube, a stirrer, and a thermocouple was chargedwith an alcohol component as listed in Table 1. The contents were heatedto 100° C., and terephthalic acid as listed in Table 1 was then addedthereto, and the mixture was heated to 160° C. An esterificationcatalyst and an esterification promoter as listed in Table 1 were addedthereto, and the mixture was heated to 235° C. and reacted at 235° C.for 10 hours, and then reacted for one hour at 235° C. and 8.0 kPa. Thereaction mixture was cooled to 160° C., and an acid modified product aslisted in Table 1 was added thereto. The temperature was then raisedagain to 235° C., and a polycondensation reaction was carried out at235° C. for 5 hours. The reaction mixture was then cooled to 200° C.,glycerol as listed in Table 1 was added thereto, and a polycondensationreaction was carried out at 200° C. for one hour, and further at 200° C.and 8.0 kPa until a softening point reached to a value as listed inTable 1, to provide an amorphous polyester resin (resin A6).

Production Example 3 of Resin

A 10-liter four-neck flask equipped with a dehydration tube equippedwith a nitrogen inlet tube, a stirrer, and a thermocouple was chargedwith an alcohol component as listed in Table 1. The contents were heatedto 100° C., and terephthalic acid as listed in Table 1 was then addedthereto, and the mixture was heated to 160° C. An esterificationcatalyst and an esterification promoter as listed in Table 1 were addedthereto, and the mixture was heated to 235° C. and reacted at 235° C.for 10 hours, and then reacted for one hour at 235° C. and 8.0 kPa. Thereaction mixture was cooled to 200° C., trimellitic anhydride as listedin Table 1 was added thereto, and a polycondensation reaction wascarried out at 200° C. for one hour, and further at 200° C. and 8.0 kPauntil a softening point reached to a value as listed in Table 1, toprovide an amorphous polyester resin (resin A7).

Production Example 4 of Resin

A 10-liter four-neck flask equipped with a dehydration tube equippedwith a nitrogen inlet tube, a stirrer, and a thermocouple was chargedwith an alcohol component as listed in Table 1. The contents were heatedto 100° C., and terephthalic acid as listed in Table 1 was then addedthereto, and the mixture was heated to 160° C. An esterificationcatalyst and an esterification promoter as listed in Table 1 were addedthereto, and the mixture was heated to 235° C. and reacted at 235° C.for 10 hours, and then reacted for one hour at 235° C. and 8.0 kPa. Thereaction mixture was cooled to 200° C., an alkenylsuccinic anhydridesubstituted with an alkenyl group having from 10 to 14 carbon atoms andtrimellitic anhydride each as listed in Table 1 were added thereto, anda polycondensation reaction was carried out at 200° C. for one hour, andfurther at 200° C. and 8.0 kPa until a softening point reached to avalue as listed in Table 1, to provide an amorphous polyester resin(resin A8).

Production Example 5 of Resin

A 10-liter four-neck flask equipped with a dehydration tube equippedwith a nitrogen inlet tube, a stirrer, and a thermocouple was chargedwith an alcohol component as listed in Table 2. The contents were heatedto 100° C., and terephthalic acid as listed in Table 2 was then addedthereto, and the mixture was heated to 160° C. An esterificationcatalyst and an esterification promoter as listed in Table 2 were addedthereto, and the mixture was reacted at 235° C. for 10 hours, and thenreacted for one hour at 235° C. and 8.0 kPa, to provide an amorphouspolyester resin (resin B1).

TABLE 1 Resin A1 Resin A2 Resin A3 Resin A4 Resin A5 g ratio g ratio gratio g ratio g ratio Alcohol BPA-PO¹⁾ 510 10 510 10 510 10 510 10 51010 component BPA-EO²⁾ 4262 90 4262 90 4262 90 4262 90 4262 90 Glycerol —— — — — — — — — — Carboxylic Terephthalic 1693 70 1693 70 1693 70 169370 1693 70 acid acid component Trimellitic 224 8 224 8 224 8 224 8 224 8A anhydride Alkenylsuccinic — — — — — — — — — — anhydride CarboxylicPIBSA³⁾ 314 4.7 628 9.4 942 14.1 1257 18.8 1570 23.5 acid componentPP/PE-g-MA⁴⁾ — — — — — — — — — — B (acid modified product)Esterification Tin(II) 33 0.5 33 0.5 33 0.5 33 0.5 33 0.5 catalyst 2-ethylhexanoate Esterification Gallic 1.3 0.02 1.3 0.02 1.3 0.02 1.3 0.021.3 0.02 promoter acid Physical Softening 139.5 140.2 140.4 139.7 141.4properties point, ° C. Highest 61.7 58.9 56.0 55.4 53.5 temperature ofendothermic peak, ° C. Softening 2.26 2.38 2.51 2.52 2.64 point/ highesttemperature of endothermic peak Glass 58.7 56.1 53.9 53.4 51.1transition temperature, ° C. Acid value, 11.5 13.4 14.6 15.5 16.1mgKOH/g Resin A6 Resin A7 Resin A8 Resin A9 g ratio g ratio g ratio gratio Alcohol BPA-PO¹⁾ 510 10 510 10 510 10 510 10 component BPA-EO²⁾3836 81 4262 90 4262 90 4262 90 Glycerol 80 6 — — — — — — CarboxylicTerephthalic 1935 80 1693 70 1693 70 1693 70 acid acid componentTrimellitic — — 224 8 224 8 224 8 A anhydride Alkenylsuccinic — — — —781 20 — — anhydride Carboxylic PIBSA³⁾ 1188 18.7 — — — — — — acidcomponent PP/PE-g-MA⁴⁾ — — — — — — 1257 18.8 B (acid modified product)Esterification Tin(II) 32 0.5 33 0.5 37 0.5 37 0.5 catalyst 2-ethylhexanoate Esterification Gallic 1.3 0.02 1.3 0.02 1.5 0.02 1.5 0.02promoter acid Physical Softening 140.8 138.7 139.8 136.5 propertiespoint, ° C. Highest 51.7 63.9 49.1 56.2 temperature of endothermic peak,° C. Softening 2.72 2.17 2.85 2.43 point/ highest temperature ofendothermic peak Glass 50.0 61.4 47.5 51.9 transition temperature, ° C.Acid value, 19.7 10.0 19.9 15.3 mgKOH/g Note) Ratios of the alcoholcomponent and the carboxylic acid component A are each expressed by amolar ratio, ratios of the carboxylic acid component B is are expressedby a mass ratio, based on 100 parts by mass of a total of the alcoholcomponent and the carboxylic acid component A, and ratios of theesterification catalyst and the esterification promoter are eachexpressed by a mass ratio, based on 100 parts by mass of a total of thealcohol component and the carboxylic acid component A, respectively. 1)Polyoxypropylene(2.2)-2,2-bis(4-hydroxyphenyl)propane 2)Polyoxyethylene(2.2)-2,2-bis(4-hydroxyphenyl)propane 3) PIBSA: anamorphous one-end modified polyisobutene succinic anhydride”H1000,”manufactured by Dover, Mw:2400, highest temperature of endothermic peak:not detected 4) PP/PE-g-MA: a crystalline random graft-form maleicanhydride-modified ethylene/propylene copolymer “TOYO-TAC MA-T,”manufactured by TOYOBO CO., LTD, softening point (98° C.)/highesttemperature of endothermic peak (93° C.) = 1.05

TABLE 2 Resin B1 Alcohol BPA-PO¹⁾ 3920 80 component BPA-EO²⁾ 910 20Carboxylic Terephthalic acid 1859 80 acid component EsterificationTin(II) 2- 33 0.5 catalyst ethylhexanoate Esterification Gallic acid 1.30.02 promoter Physical Softening point, ° C. 105.4 Properties Highesttemperature of endothermic 62.5 peak, ° C. Softening point/highesttemperature 1.69 of endothermic peak Glass transition temperature, ° C.59.8 Acid value, mgKOH/g 1.6 Note) Ratios of the alcohol component andthe carboxylic acid component are each expressed by a molar ratio; andratios of the esterification catalyst and the esterification promoterare each expressed by a mass ratio, based on 100 parts by mass of atotal of the alcohol component and the carboxylic acid component,respectively. ¹⁾Polyoxypropylene(2.2)-2,2-bis(4-hydroxyphenyl)propane²⁾Polyoxyethylene(2.2)-2,2-bis(4-hydroxyphenyl)propane

Examples 1 to 7 and Comparative Examples 1 to 4

One-hundred parts by mass of a resin binder as listed in Table 3, 6parts by mass of a colorant “Fastogen Supenuagenda R” (C.I. Pigment Red122, manufactured by Dainippon Ink and Chemicals Incorporated), 1 partby mass of a charge control agent “LR-147” manufactured by Japan CarlitCo., Ltd., and 4 parts by mass of a releasing agent “SP-105”manufactured by S. Kato & CO., Fischer-Tropsch wax, melting point: 105°C. were thoroughly stirred with a Henschel mixer. Thereafter, themixture was melt-kneaded with a co-rotating twin-screw extruder of whichkneading member had a full length of 1560 mm, a diameter of screw of 42mm, and an inner diameter of barrel of 43 mm. The rotational speed ofthe roller was 200 r/min, and a heating set temperature within theroller was 100° C., the temperature of the kneaded product was 160° C.,the feeding rate of the kneaded product was 10 kg/h, and the averageresidence time was about 18 seconds. After cooling, toner particleshaving a volume-median particle size D₅₀ of 6.5 μm were obtained with ajet mill.

Here, in the process of producing the toner particles, 1 kg of amelt-kneaded product (a square piece of about 3 cm each side) wassupplied into Rotoplex manufactured by Hosokawa Micron Corporation(Model R20/10) attached with a screen with a sieve opening of 3 mm, tocarry out pulverization. All the pulverized products were dischargedthrough the screen in about 20 minutes, and a volume-median particlesize D₅₀ of the particles obtained was measured with Nippon Laser(HELOS) under the model number of QICPIC/R. The productivity wasevaluated in accordance with the following evaluation criteria. Theresults are shown in Table 3.

[Evaluation Criteria]

S: The productivity is less than 10.0, causing no troubles in theproductivity of the resin during the production of toner.A: The productivity is 10.0 or more and less than 18.0, causing notroubles during the production of toner with minor adjustments in theproduction conditions.B: The productivity is 18.0 or more and less than 26.0, causing notroubles during the production of toner with some modifications in theproduction conditions.C: The pulverizability is 26.0 or more, so that the productionefficiency is somewhat lowered even though the production of toner isfeasible.

To 100 parts by mass of the toner particles obtained was added 2 partsby mass of a hydrophobic silica “Aerosil R972” manufactured by Nippon

Aerosil Co., Ltd., hydrophobic treatment agent: DMDS, average particlesize: 16 nm as an external additive, and the mixture was mixed with aHenschel mixer at 3,600 r/min for 5 minutes, to provide each of thetoners.

Test Example 1—Low-Temperature Fusing Ability

Each of the toner was loaded to a color printer manufactured by Oki DataCorporation under the trade name of “C612dnw,” and an image was printedout in an unfused state (print coverage area: 6 cm×6 cm, 0.5 mg/cm²).

An unfused image was allowed to fuse with a fusing device of the aboveprinter offline at 100 mm/sec with raising the temperature from 100° C.with an increment of 5° C. Here, as a paper to be fused, “J sheet”manufactured by Fuji Xerox, a basis weight: 82 g/m², and a paperthickness: 97 μm was used.

“UNICEF Cellophane” tape, MITSUBISHI PENCIL CO., LTD., width: 18 mm, JISZ-1522, was adhered to the fused images, and the resulting fused imageswere allowed to pass through a fusing roller set at 30° C., and the tapewas then removed. The optical reflective densities of the image beforeadhesion of the tape and after removal of the tape were measured with areflective densitometer “RD-915” manufactured by Macbeth ProcessMeasurements Co. The temperature of a fusing roller at which thepercentage of the optical reflective densities (after removal of thetape/before adhesion of the tape) initially exceeds 90% is defined asthe lowest fixing temperature, and the low-temperature fusing abilitywas evaluated. The results are shown in Table 3.

Test Example 2—Hygroscopic Resistance

The particle sizes of the resin used in a resin binder were evenly sizedto from 150 to 250 μm, and the resin was dried for 12 hours with avacuum dryer at 40° C. and 60 torr. The mass thereof after drying (resinmass a) was measured. The amount 2.00 g of a dried resin was evenlyspread over a glass petri dish, and allowed to stand for 12 hours underhigh-temperature, high-humidity environmental conditions of 40° C. and ahumidity of 85%, and the mass was then again measured (resin mass b).

The smaller the hygroscopicity ratio (%) calculated from

(Resin mass b−Resin mass a)/Resin mass a×100,

the more excellent the hygroscopic resistance, and the hygroscopicresistance was evaluated in accordance with the following evaluationcriteria. The results are shown in Table 3.

<Evaluation Criteria>

A: A hygroscopicity ratio is less than 0.3%, so that the chargeabilityof the toner is not affected thereby.B: A hygroscopicity ratio is 0.3% or more and less than 0.6%, so thatthe chargeability of the toner is not substantially affected even thoughthere is a possibility of slightly lowering the chargeability.C: A hygroscopicity ratio is 0.6% or more and less than 0.9%, so thatthere is a possibility of lowering the chargeability of the toner.D: A hygroscopicity ratio is 0.9% or more and less than 1.2%, so thatthere is a high possibility of lowering the chargeability of the toner.E: A hygroscopicity ratio is 1.2% or more, so that the chargeability ofthe toner is lowered, thereby giving causations to development failures.

Test Example 3—Initial Rise in Charging

A 20 mL polypropylene bottle was charged with 4 parts by mass (0.4 g) ofa toner and 96 parts by mass (9.6 g) of a silicone ferrite carriermanufactured by KANTO DENKA KOGYO CO., LTD. (average particle size: 90μm), under the environmental conditions of a temperature of 25° C. and arelative humidity of 50%, and the components were mixed with a ball-millfor 0.5 minutes, and electric charges of the toner were determined witha “q/m Meter MODEL 210HS” manufactured by TREK. Subsequently, thecontents were stirred for additional 2.5 minutes, and electric chargeswere determined. A value of a ratio of two electric charges (electriccharges at 0.5 minutes/electric charges at 2.5 minutes) was calculated.The larger the calculated value, the more excellent the initial rise incharging. The initial rise in charging was evaluated in accordance withthe following evaluation criteria. The results are shown in Table 3.

<Evaluation Criteria>

A: A calculated value is 0.80 or more, so that printing failure due todevelopment failure is not generated even when printed at high speeds(50 sheets or more).B: A calculated value is 0.60 or more and less than 0.80, so that thereis a slight possibility that printing failure due to development failureis generated when printed at high speeds, but no substantial troubles.C: A calculated value is 0.40 or more and less than 0.60, so thatprinting failure due to development failure is generated when printed athigh speeds.D: A calculated value is less than 0.40, so that printing cannot becarried out due to development failure when printed at high speeds.

TABLE 3 Evaluations of Toner Resin Binder Low-temperature Parts byfusing ability, Hygroscopic Initial rise in Kinds mass Productivity ° C.resistance charging Ex. 1 Resin A1 100 B 20.2 150 B 0.39% B 0.71 Ex. 2Resin A2 100 A 15.2 150 B 0.32% B 0.78 Ex. 3 Resin A3 100 A 14.2 150 A0.27% A 0.84 Ex. 4 Resin A4 100 A 14.4 150 A 0.22% A 0.89 Ex. 5 Resin A5100 B 19.8 155 A 0.18% A 0.93 Ex. 6 Resin A4 90 S 9.8 145 A 0.28% A 0.82Resin B1 10 Ex. 7 Resin A6 100 A 16.4 150 A 0.27% A 0.83 Comp. Resin A7100 C 32.2 150 A 0.22% A 0.82 Ex. 1 Comp. Resin A7 80 B 22.4 145 C 0.77%C 0.55 Ex. 2 Resin B1 20 Comp. Resin A8 100 C 34.5 150 A 0.19% A 0.81Ex. 3 Comp. Resin A9 100 C 30.8 150 A 0.20% A 0.81 Ex. 4

It can be seen from the above results that the toners of Examples 1 to 7are excellent in all of hygroscopic resistance, initial rise incharging, and productivity, while maintaining favorable low-temperaturefusing ability. In particular, it can be seen in the toner of Example 6in which a low-softening point resin containing a large amount oflow-molecular weight components excellent in pulverizability and ahigh-softening point resin introduced with an acid modified productexcellent in productivity are used together that the low-softening pointresin and the high-softening point resin can be homogeneously mixed froman initial state when kneading the toner, so that the toner isespecially excellent in all the points of hygroscopic resistance,initial rise in charging, and productivity.

On the other hand, the toner of Comparative Example 1 containing apolyester resin without using an acid modified product isdisadvantageous in productivity. In addition, the toner of ComparativeExample 2 in which the polyester resin of Comparative Example 1 is usedtogether with a low-softening point polyester resin, has loweredhygroscopic resistance and the initial rise in charging even though theproductivity can be improved. In addition, the toner of ComparativeExample 3 containing a polyester resin in which an amorphous monomerhaving an alkyl group (alkenylsuccinic anhydride) is used in place ofthe acid modified product does not form a micro-phase separation statewhich is assumed to be caused because the amorphous alkenyl group is notcrystallized in the polyester resin, so that the productivity is notimproved but rather pulverizability is worsened due to the soft segment(alkenyl group). The toner of Comparative Example 4 containing apolyester resin using a crystalline macro-monomer having an alkyl groupsuch as an acid modified product of an α-olefin having 2 or 3 carbonatoms does not have improved productivity which is assumed to be causedbecause dispersibility in the polyester resin and the phase separabilityare worsened even though the reducing effects of hydroscopic resistanceare found.

The resin binder composition for toners of the present invention issuitably used for a toner for electrostatic image development which isusable in development of latent images formed in, for example,electrostatic image development method, electrostatic recording method,electrostatic printing method or the like.

1. A resin binder composition for toners, comprising: a polyester resinA which is a polycondensate A of raw materials A comprising an alkyleneoxide adduct of bisphenol A, an aromatic dicarboxylic acid compound, atrivalent or higher polyvalent raw material monomer which is at leastany one members of a trihydric or higher polyhydric alcohol and atricarboxylic or higher polycarboxylic acid compound, and an amorphousacid modified product A of an α-olefin polymer having 4 or more carbonatoms and 18 or less carbon atoms, the polyester resin A having asoftening point of 120° C. or more and 150° C. or less, wherein theα-olefin polymer having 4 or more carbon atoms and 18 or less carbonatoms is a polyisobutene-based polymer.
 2. The resin binder compositionfor toners according to claim 1, wherein the polycondensate A is apolycondensate of a polycondensate B of raw materials B comprising analkylene oxide adduct of bisphenol A, an aromatic dicarboxylic acidcompound, and an amorphous acid modified product A of an α-olefinpolymer having 4 or more carbon atoms and 18 or less carbon atoms, withthe trivalent or higher polyvalent raw material monomer.
 3. The resinbinder composition for toners according to claim 2, wherein thepolycondensate B is a polycondensate of a polycondensate C of rawmaterials C comprising an alkylene oxide adduct of bisphenol A and anaromatic dicarboxylic acid compound, with the amorphous acid modifiedproduct A of an α-olefin polymer having 4 or more carbon atoms and 18 orless carbon atoms.
 4. The resin binder composition for toners accordingto claim 1, wherein the content of the trivalent or higher polyvalentraw material monomer is 2% by mol or more and 18% by mol or less of theraw material A other than the acid modified product A.
 5. The resinbinder composition for toners according to claim 1, wherein theamorphous acid modified product A of an α-olefin polymer having 4 ormore carbon atoms and 18 or less carbon atoms is an acid modifiedproduct in which the α-olefin polymer having 4 or more carbon atoms and18 or less carbon atoms is modified with at least one acid selected fromthe group consisting of maleic acid, fumaric acid, itaconic acid, andanhydrides of these acids.
 6. The resin binder composition for tonersaccording to claim 1, wherein the amorphous acid modified product A ofan α-olefin polymer having 4 or more carbon atoms and 18 or less carbonatoms is an acid modified product in which an end or ends of theα-olefin polymer having 4 or more carbon atoms and 18 or less carbonatoms are modified with an acid.
 7. The resin binder composition fortoners according to claim 1, wherein the amorphous acid modified productA of an α-olefin polymer having 4 or more carbon atoms and 18 or lesscarbon atoms is an acid modified product in which one end of theα-olefin polymer having 4 or more carbon atoms and 18 or less carbonatoms is modified with an acid.
 8. The resin binder composition fortoners according to claim 1, wherein a weight-average molecular weightof the amorphous acid modified product A of an α-olefin polymer having 4or more carbon atoms and 18 or less carbon atoms is 500 or more and5,000 or less.
 9. The resin binder composition for toners according toclaim 1, wherein the content of the amorphous acid modified product A ofan α-olefin polymer having 4 or more carbon atoms and 18 or less carbonatoms is 3 parts by mass or more and 40 parts by mass or less, based on100 parts by mass of a total amount of the raw materials A other thanthe acid modified product A.
 10. (canceled)
 11. A toner forelectrostatic image development, comprising a resin binder compositionfor toners as defined in claim
 1. 12. The resin binder composition fortoners according to claim 1, wherein the amorphous acid modified productA of the α-olefin polymer having 4 or more carbon atoms and 18 or lesscarbon atoms is a polyisobutene succinic anhydride modified with maleicanhydride at one end.
 13. The resin binder composition for tonersaccording to claim 1, wherein the tricarboxylic or higher polycarboxylicacid compound comprises a trimellitic acid compound.
 14. The resinbinder composition for toners according to claim 1, wherein the alkyleneoxide adduct of bisphenol A is a compound represented by the formula(I):

wherein OR and RO are an oxyalkylene group, wherein R is an ethylenegroup and/or a propylene group; and each of x and y is a positive numbershowing an average number of moles of alkylene oxide added, wherein avalue of the sum of x and y is 1 or more and 16 or less, and wherein thecontent of the alkylene oxide adduct of bisphenol A represented by theformula (I) in the alcohol component is 70% by mol or more.
 15. Theresin binder composition for toners according to claim 1, wherein thearomatic dicarboxylic acid compound comprises terephthalic acid.
 16. Theresin binder composition for toners according to claim 1, wherein thecontent of the polyester resin A in the resin binder composition is 80%by mass or more.
 17. The resin binder composition for toners accordingto claim 1, further comprising a polyester resin B having a softeningpoint lower than that of the polyester resin A.
 18. The toner forelectrostatic image development according to claim 11, wherein thecontent of the resin binder composition in the toner is 50% by mass ormore and less than 100% by mass.
 19. The toner for electrostatic imagedevelopment according to claim 11, which is a pulverized toner obtainedby melt-kneading method.
 20. The toner for electrostatic imagedevelopment according to claim 11, wherein the volume-median particlesize of the toner is 3 μm or more and 15 μm or less.